With development of digital technologies, an audio/video (AV) service has been changing from a passive/uni-directional AV service to a user-participant AV service. A freeview AV service denotes a user-oriented realistic audio and video service that enables a user to readily select and view the user's desired viewpoint and listening point as if the user is navigating a scene.
In the case of a general multimedia service, a service usually includes a single audio object and a single video object. A Motion Picture Experts Groups (MPEG)-4 system standard defines a multimedia service that includes a plurality of objects. Also, the freeview AV service may be multimedia content that includes a plurality of objects, which is similar to the defined MPEG-4 system standard.
Also, the MPEG-4 system standard such as International Standardization Organization (IOS)/International Electrotechnical Commission (IEC) 14496-1 defines a file format of a content that includes a plurality of objects. The file format according to the MPEG-4 system standard includes Binary Format for Scenes (BIFS) corresponding to three-dimensional (3D) scene information of objects, OD corresponding to object information, index information that is accessible to a stream of each object, and object stream data such as BIFS, OD, and the like. In this instance, each object data may exist in the file or may exist in another file.
The index information associated with each object stream may be classified and stored for each object. Each object stream may also be classified and stored for each stream. The above scheme is flexibly defined to receive all the types of objects, such as audio, video, still images, and the like.
The MPEG-4 system may change 3D scene information through a user interaction using BIFS data and a BIFS command. In this instance, the BIFS data needs to be appropriately created in the stage of copyrights. A terminal may need to interpret the BIFS command. The MPEG-4 system includes a function for various types of user interactions, which may require relatively complex operations in the stage of copyrights or the play terminal.
However, the MPEG-4 system standard defines the file format that includes all the diversified media such as audio, video, still images, and the like, whereas freeview AV contents include the same kind of multiple objects. Accordingly, there is a need for a file format that can more effectively store contents in comparison to the file format defined in the existing MPEG-4 system standard and can enhance readiness of access to each object.